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Help! I'm losing my bearings!
Posted: Thu Jan 31, 2013 7:18 pm
by Coalmossian
I'm not really, but as I said in one or two of my other postings, I'm back to this mechanicing (?) game after an absence of at least thirty years so I've forgotten most of what little I knew, and I don't have a lot of self-confidence in this sort of stuff!
I'm in the process of rebuiding my front and rear suspension/brakes/hubs etc and it seemed a tad foolish to make everything clean and bonnie and shinily painted and not change the bearings and oilseals as well, even though the bearings appear fine. Vehicle's done 54,000 miles.
So, I bought new bits from Bull Motif, and the rear bearings were quite easy to change ( any markings on the outer ballrace to the outside, yes?)
However the front ones are a tad more tricky so I'm hoping someone out there ( bmcecosse, brucek, 1mustard.............ANYONE) will reply with an idiot-proof, step by step guide to replacing them.
So far I've inserted the larger, inner bearing with the wider, outer ballrace lip to the inside of the hub so that it is adjacent to the tapered spacer. Correct?
Now I have the smaller outer bearing to put in! One face of it is completely flat, while the other face has the centre ballrace four or five mm proud of the outer ballrace. Which face should go adjacent to the spacer, ie, face the center of the hub? I believe it is the one that says "thrust"so that the proud centre ballrace faces the brake drum, yes?
Then I believe that the oil seal should be inserted with the coilspring visible from the outside of the hub?
Have I got it right? Don't want my wheels falling off or ennifink like that 'appenin'!
Thanks in advance for your anticipated help and advice.
Must get around to doing one of these signature things!

Re: Help! I'm losing my bearings!
Posted: Thu Jan 31, 2013 8:40 pm
by mike.perry
The oil seal should fit with wire inside, not visible.
Quite honestly I would have left well alone, if it ain't broke don't fix it.
Far more important are the top and bottom swivels and the braking system and once you have got that lot sorted you will have enough problems to keep you busy
Re: Help! I'm losing my bearings!
Posted: Thu Jan 31, 2013 8:59 pm
by bmcecosse
I'm not going to be drawn on this - and yes - best left well alone. I have NEVER had any bearing problems - front or rear. Even with the oil seal - there is the question of whether it is there to keep grease in - or dirt out....your view on that decides which way round it should be fitted !
Re: Help! I'm losing my bearings!
Posted: Thu Jan 31, 2013 11:11 pm
by lambrettalad
how did the old ones come out? Ithink it it so easy theses days to take pictures and see the results immediately ,so it's very easy to trace a job ,from start to finish
Re: Help! I'm losing my bearings!
Posted: Thu Jan 31, 2013 11:22 pm
by IslipMinor
The thick part of the outer races, which have the maker's name and data on it, face the inside of the hub and also face each other - the picture below shows how they fit:
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The 2 bearings on the top row of this next picture show the 'thick' side of the outer race - they face the inside of the hub so that the thin sides of the inner races are against the tapered spacer:
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Re: Help! I'm losing my bearings!
Posted: Thu Jan 31, 2013 11:49 pm
by bmcecosse
Make sure you haven't been sold 'C3' bearings - the clearance is too loose for a wheel bearing.....
Re: Help! I'm losing my bearings!
Posted: Fri Feb 01, 2013 11:29 am
by les
Oil seal round the wrong way on diagram?
Re: Help! I'm losing my bearings!
Posted: Fri Feb 01, 2013 12:37 pm
by IslipMinor
Oil seal round the wrong way on diagram?
For clarity the wire spring in the oil seal faces into the hub.
Is this better?
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Re: Help! I'm losing my bearings!
Posted: Fri Feb 01, 2013 5:49 pm
by Coalmossian
I think that there is a definite message here................ask first and act later!!! When I posted this, I had already dismantled the first hub, so I was a bit too hasty. Reading your replies, for which I thank you all very much indeed, apart from getting the distinct feeling that I should have just left well alone, I get the feeling that there is a certain amount of conflictiing opinion on the matter.
Anyway, the outcome is this! With the one hub I had dismantled, I had to replace the larger, inner bearing as the old one had, predictably, disintegrated. So I replaced that with the new one from the Bull Motif kit, and then, having become even more confused as the smaller outer bearing that came with that kit bore little resemblance ( other than in overall size!) to the old one, I reinstated the old one.
The second hub I have left well alone other than removing a wee bit of old grease and replacing it with some new molybdenum grease!
As for the seal, I shall follow the advice given here in your replies, but the Haynes manual seems to say the opposite!
Now, as to this new outer ( smaller diameter) bearing! I phoned B. M. and was told that the proud, inner race ( you'll see from the photos) should face inwards adjacent to the spacer. But that would mean that the word "thrust" on the outer ballrace would be facing outwards, and all info I've seen says otherwise! That's why I opted for tha "auld een"!
Any comments on this would be welcome.This first picture shows the flat or planar surface which has the word "thrust" at the top on the outer ballrace which according to B. M. would have been facing out of the hub.[frame]

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This second picture shows the bearing's profile, with the flat face at the bottom[frame]

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I hope that I don't ever need to mess about with them again if I'm honest, but next time I'll try to remove them and just pop along to my local Scotbearings branch. Incidentally I'm not too keen on the new ones with what seems to be a black plastic cage. I prefer the old ones with the brass cage.....it seems more substantial. But maybe I'm just showing my ignorance?
Once again, thanks to all who have commented and offered advice, especially Islipminor for the time and trouble you have taken with the diagrams and photos.
Re: Help! I'm losing my bearings!
Posted: Fri Feb 01, 2013 6:28 pm
by IslipMinor
Intriguing bearing! Looking at the pictures of your bearings, they are unlike anything I have seen before, with the 'half-width' outer race - what is the bearing reference? The inner, larger, bearing should be a 7205B and the outer a 7303B - both are 40° angular contact bearings.
The BMC Service Manual states that the 'thrust' side of the bearing faces the spacer. Even though 'your' design is not the normal 'standard', looking at the pictures, the same principle applies and the 'thrust' sides must both face the spacer - if they do not, the wheel will fall off - it is just a matter of how long it takes, not whether it will or not! We have had extensive postings on this, and it DOES matter which way round the bearings are fitted.
As a reminder from previous postings, the diagram below shows how the hub will detach itself from the front suspension upright if the bearings are fitted the wrong way round - please don't do it, it won't be just your bearings that you lose!
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Re: Help! I'm losing my bearings!
Posted: Fri Feb 01, 2013 7:37 pm
by bmcecosse
As I said earlier - the installation of the seal depends on your view whethere it is better to keep dirt out - or to keep grease in. On Mini front hubs for example - the seal is put on reversed in order to try to keep dirt/water out. The same argument could be applied to Minor hubs - although grease escaping could be bad for the brakes - and the inner end of the hub is pretty much protected by the brake backplate.
Re: Help! I'm losing my bearings!
Posted: Fri Feb 01, 2013 8:57 pm
by IslipMinor
Roy,
Do you have a picture from the Mini manual showing a reversed seal? The only one I have shows the seals in the conventional 'Retention' orientation, i.e. the spring side facing the bearings - see below:
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Item 8 is described as a water shield, presumably to protect the seal from excessive contact with external contaminants?
SKF, who invented the lip seal back in 1928, have the application of 'Exclusion', i.e. reversing the orientation to keep contaminants out of the bearing enclosure. However, they warn about potential 'excessive oil loss' if oil is the non-spring side of the seal, and I wonder how thin the grease becomes after an hour or so's driving?
Would seem sensible to stick with the manufacturer's standard of installing the seal lip facing the bearings.
Re: Help! I'm losing my bearings!
Posted: Fri Feb 01, 2013 10:25 pm
by les
An oil seal doesn't have to face outwards to keep dirt out! The simple fact that it's there does that. It's an OIL seal after all and it should be sealing any oil/grease from escaping from inside! Which it won't do if facing out. I think you've got that one wrong Roy. Item 8 was often supplied with mini bearings.
Re: Help! I'm losing my bearings!
Posted: Fri Feb 01, 2013 11:14 pm
by bmcecosse
Oh yes - you MUST have the outer shield too - but the seal is best fitted outwards to keep the crap out - and yes - I know that wasn't the factory method.
Re: Help! I'm losing my bearings!
Posted: Fri Feb 01, 2013 11:18 pm
by les
I'm really surprised to hear you are serious about the seal being fitted that way! What force is there to push dirt in? The correct way round even has a flat surface ! Anyhow, hope you like my new signature pic.
Re: Help! I'm losing my bearings!
Posted: Fri Feb 01, 2013 11:20 pm
by bmcecosse
Twin oil coolers - hahahahah Was it your car??
Re: Help! I'm losing my bearings!
Posted: Fri Feb 01, 2013 11:30 pm
by les
No just a picture I've had for years, I think it was called Vitamini !!
Re: Help! I'm losing my bearings!
Posted: Fri Feb 01, 2013 11:39 pm
by IslipMinor
From the previous diagram and other info, the inner seal has a projection on the outside of the moulding that is designed to fit inside the water shield. How can that be fitted the opposite way round, or did you use a similar sized seal and do away with the water shield? Without the projection the water shield has nothing to shield!
The rear projection is arrowed in
red:
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Re: Help! I'm losing my bearings!
Posted: Fri Feb 01, 2013 11:48 pm
by bmcecosse
I always used standard seals from the local bearing place. And of course - taper roller bearings - the ball bearings are hopeless. I think at one point I may have got hold of some double lipped seals - it was a while ago now !!
Re: Help! I'm losing my bearings!
Posted: Sat Feb 02, 2013 12:06 am
by IslipMinor
Twin oil coolers
I have an MG Metro water cooled oil cooler, which has worked very well, but over the years the engine spec has changed a bit and the oil temperature began to climb up to 130°C or more on track days, so I started sorting out an oil cooler that would fit in front of the radiator.
The oil is Castrol full synthetic, but even for that it is towards the high limit, and there is not a lot of room behind the grille at the best of times, and even less when the centre part is taken up with the electric cooling fan. So I wondered about 2 small ones in series, and then found a nice long slim one from a Saab and began to make up the mounting brackets for it.
Then thought I should check the calibration of the electric oil temperature gauge - to find that it was over-reading at 100°C by at least 20°C!! Quick bit of recalibration and all back to normal again. (Yes it does have the 10v stabiliser!).